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## Task
Implement city selection interaction

Add click handlers to each card. On click, set the selected city, visually highlight the chosen card, and immediately update the main clock to show that city's timezone, name, and date without page reload.

Current phase: Interactivity & Dynamic Rendering

Project context: الساعة العالمي — الساعة العالمية في جيبك

## Deliverable quality baseline (applies to user-facing output)
If this task produces or changes anything the user sees in a browser, the result must look deliberately crafted — never scaffold-like or raw default markup:
- Clear visual hierarchy: a real page structure with headings, grouping and whitespace — not a bare dump of unstyled elements.
- Deliberate typography and spacing: readable font sizes and line-height, consistent padding/margins; interactive controls (buttons, inputs, links) must be visibly styled, never browser-default only.
- A coherent, restrained color palette (background, text, accent) with accessible contrast.
- Responsive layout: the page must stay usable on a narrow (mobile) viewport.
- Interactions must genuinely work: every control the description asks for performs the requested behavior, and purely local behavior (e.g. a confirmation/status message on click) is implemented client-side — no external service is needed for simple local feedback.
- Accessibility basics: semantic HTML, labels for inputs, alt text for images.
- Arabic/RTL correctness: the document must set lang="ar" and dir="rtl", declare UTF-8 charset, and use natural Arabic wording and typography (no machine-stiff phrasing, no reversed or Latin-mixed layout artifacts).
This is a minimum quality floor, not a template: keep full creative freedom in design, layout and copy.

Acceptance criteria:
- Implement the task: Implement city selection interaction
- Cover the task description above.
- Keep the change scoped to what this task needs.
- Do not introduce secrets or credentials in code.
- Leave the repository in a consistent state (no stray debug output).
- User-facing output must satisfy the deliverable quality baseline above (deliberate styling, responsive layout, working interactions).
- The deliverable must be a correct Arabic RTL document (lang="ar", dir="rtl", UTF-8) with polished Arabic content.